Business Property Relief used to be unlimited. Qualifying business assets passed free of Inheritance Tax whatever they were worth, which is why so many family firms survived the death of their founder intact.
Since 6 April 2026, that is no longer the position. The 100% rate now applies only to the first £2.5 million of qualifying business and agricultural property combined. Anything above the allowance attracts relief at 50%, producing an effective Inheritance Tax rate of 20% on the excess.
Three points are worth holding on to.
First, the £2.5 million is a single combined allowance covering business and agricultural property together — not one allowance for each.
Second, and this is the reassuring part, any unused allowance transfers to a surviving spouse or civil partner. A couple can shelter up to £5 million at the 100% rate, and up to £5.65 million once the nil rate bands are added. The transfer applies even if the first death was before 6 April 2026 — but the claim has to be made, not assumed.
Third, AIM-quoted and other unlisted market shares attract 50% relief in all cases and get no benefit from the 100% band.
The arithmetic only bites above the allowance. A couple owning an £8 million trading company, with both allowances available, face relief at 50% on £3 million — leaving £1.5 million chargeable and a bill of around £600,000 on the second death. Below £5 million of qualifying assets, a couple who have planned properly may face no charge at all.
Nobody has to sell anything or split the company. It is a valuation question and a drafting question, and both are easier to deal with now than later.